MspA porin is a membrane porin

Porin

Porin may refer to:* Porin , a transmembrane protein* Porin , a Croatian grand Opera, first performed in 1897* Porin , the Croatian national music industry award, first awarded in 1994 and named after the opera...

 produced by Mycobacteria, allowing hydrophilic nutrients to enter the bacterium. The protein forms a tightly interconnected octamer with eightfold rotation symmetry that resembles a goblet and contains a central channel. Each subunit fold contains a beta-sandwich of Ig-like topology and a beta-ribbon arm that forms an oligomeric transmembrane barrel.